Cutting presses



Nov. 17, 1970 'r. B. PREW 3,541,586

CUTTING PRESSES Filed June a. 1968 2 1o 17 l 10 11 2 fi }r1:{///////////////////////A V/// l I CONTROL 100 MEANS h 29 2O INVENTOR wait zigfiwy/p fluzia/ ATTORNEY United States Patent U.S. Cl. 83527 5 Claims ABSTRACT OF THE DISCLOSURE A cutting press having upper and lower relatively movable platenswith a cutter assembly therebetween having at least one cutting knife for cutting sheet workpieces when the platens are moved together and incorporating control means for controlling the movement of the platens. To ensure that the platens are correctly halted when the knife has just cut through the workpiece regardless of the height of the knife there is provided a gauge member having a height corresponding to that of the knife arranged on one of the platens. The gauge member engages a probe arranged on the other of the platens to thereby actuate the control means.

BACKGROUND OF THE INVENTION Cutter presses normally have upper and lower platens with a cutter assembly therebetween. The platens are moved together, usually hydraulically, to cause the knife or knives of the assembly to cut through one or more sheet workpieces by being forced therethrough due to the movement of the platens. It is important that the platens of the press should come to within a pre-determined distance of one another so that the knife or knives is, or are, forced completely through the workpiece to produce a clean cut but it also is important that the knife or knives should not be damaged as a result of the platens of the press coming too close together.

To ensure that the platens of the press close to the desired extent it is usual to have control means with a limit switch which can be arranged to halt the platens at a predetermined desired distance from one another. The setting of such a limit switch is a time consuming and exacting operation and so with this kind of control it is not practical to alternate frequently between varying heights of cutting knives requiring corresponding changes in the setting of the limit switch.

An object of the invention is to enable a press of the kind specified to be used with varying heights of knives without necessitating extensive re-adjustments whenever a cutting knife is changed.

SUMMARY OF THE INVENTION According to the present invention in a cutter press comprising:

(a) Upper and lower platens movable relative to one another;

(b) Drive means for moving the platens relative to one another;

(c) A cutter assembly including at least one cutting knife disposed between the platens to cut workpieces when the platens are moved together; and

(d) Control means for controlling the movement of the platens, the improvement comprising a gauge member arranged between the platens having a height corresponding to the height of the cutting knife and a probe operably connected to the control means to actuate the control means when engaged by said gauge member.

3,541,586 Patented Nov. 17, 1970 According to another aspect of the invention in or for a cutter press comprising:

(a) Upper and lower platens movable relative to one another;

(b) Drive means for moving the platens relative to one another; and

(c) Control means with a probe mounted on one of the platens for controlling the operation of the drive means, a cutter assembly with at least one cutting knife and a gauge member of a height corresponding to the height of said knife, which gauge member can engage the probe to actuate the control means when in use.

Various other aspects of the invention will become more apparent from consideration of a constructional embodiment thereof.

BRIEF DESCRIPTION OF DRAWING A constructional embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing which is a diagrammatic cross section through part of a press made in accordance with the invention.

DESCRIPTION OF PREFERRED EMBODIMENT A cutter press comprises two relatively movable platens and it can be assumed in this example that the platen designated 11 is an upper platen and the platen designated 12 is a lower platen. The upper platen 11 is slidably mounted on four columns (not shown) so that it can be moved towards and away from the lower platen 12 in a uniform manner. The upper platen 11 can be moved along the columns by means of one or more hydraulic rams 102 or some other equivalent drive means. A control means generally designated which may be electrical controls the operation of the ram so that the upper platen 11 can be stopped at a pre-determined distance from the lower platen 12. The control means hitherto has been usually operated by a simple limit switch which is contacted by the upper platen 11 when it reaches the desired lowermost position.

Returning to the drawing, a cutter assembly 13, such as a form cutter, is mounted on the lower platen 12 and a backing plate 15 is carried by the upper platen 11. The cutter assembly 13 is equipped with cutting blades or knives 14 which extend upwardly from the assembly 13 towards the upper platen ,11. In operation, one or more workpieces (not shown) are laid over the knives 14 between the two platens 11 and 12 and the upper platen 11 is then lowered by the hydraulic ram until the plate 15 secured to the upper platen 11 presses the workpiece or workpieces onto the knives 14 and causes the knives 14 to cut them to the desired shape dictated by the assembly 13. It is important that the plate 15 should come into contact with the knives 1 4 to ensure a clean cut, but it is also important that the hydraulic ram should not drive the plate 15 beyond the point where it contacts the knives 14 because this would damage either the knives 14 or the plate 15 or both. This control action as effected by the control means 100 has hitherto been extremely difficult to set up, and necessitated periodic re-checking.

In addition to the knives 14 the drawing also shows, in chain dotted lines, alternative knives 24 which are deeper than the knives 14. A further alternative length of knives, smaller than the knives 14, is indicated by the dotted knife edge 34. It is clear that when the knives 24 or 34 are used in place of the knives 14 the position at which the platen 11 is stopped as it descends in a cutting operation should be made to correspond with the height of the knives being used.

With a conventional press, where generally a simple limit is used to set the lowermost position of the upper platen 11, it is not practical to alternate between various heights of knives because at each change of knife depth a time-consuming setting operation is required.

The present invention is concerned with overcoming this problem and with eliminating the time consuming setting operation. In accordance with the invention the upper platen 11 is provided with a probe 16 which is connected through a linkage, shown diagrammatically at 17, to a switch 18 which is actuated by upward movement of the probe 16 to thereby cause the control means to stop downward movement of the upper platen 11 by cutting off the supply of hydraulic pressure medium to the hydraulic ram. A gauge member 19 is mounted on the lower platen 12 and is disposed below the probe 16. The member 19. has an upper abutment surface 20 attached to legs 21 which are mounted on the lower platen 12 so that the surface 20 is parallel to the platens 11, 12. In particular, the legs 21 extend through holes 22 in the cutter assembly 13 and are attached thereto. The arrangement is such that when the probe 16 engages the surface 20 the probe 16 actuates the switch 18 which in turn causes the control means to halt and prevent further downward movement of the upper platen 11. The gauge member 19 is of such a vertical height that the surface 20 engages and cooperates with the probe 16 to cause the upper platen 11 to stop in its downward movement in the position required when the knives 14 are being used. When deeper knives such as the knives 24 are being used, a different gauge member of correspondingly greater height such as the gauge member 29, shown in chain dotted lines, is used. For other lengths of knives other gauge members having heights corresponding to the length of the knives are used.

In practice, the knives used are an integral part of a cutter assembly such as 13 and so a gauge member such as 19 or 29, depending on the length of the knives fixed in the cutter assembly, is preferably permanently allocated to the cutter assembly in question and in fact is preferably attached to it within the holes 22 as at 101.

If the press is provided with the usual limit switch to regulate the lowermost position of the upper platen 11, this switch can be set to a position corresponding to the knives 34 of smallest height which are to be used in the press; thus, with these smaller knives 34 no gauge member such as 19 or 29 is required.

With a press equipped with a probe 16 and the associated parts 17 and 18 and a series of cutter assemblies equipped with knives of different heights and gauge members of height corresponding to the height of the knives, any cutter assembly in conjunction with one or more workpieces to be cut, can be inserted into the press and the workpieces cut without the necessity for setting the press for the height of the knives concerned. This is of particular importance in presses used for cutting workpieces used in the motor industry, because diflfering heights of knives are used with differing materials such as carpets and upholstery material.

Although the invention has been described with a probe 16 and gauge member 19 of fairly small size, if it is desired that the cutter assembly 13 should not have to be positioned accurately on the lower platen, either the probe 16 or the gauge member 19 or both these parts can be extended to ensure that they always engage with each other as the upper platen is lowered. The gauge member 19 may, for example, extend along the whole length of the knife 14 at one side thereof. To avoid the complications of providing a single gauge strip throughout the length of the cutter such a gauge member 19 may be made up of portions of convenient length.

In an alternative to the arrangement shown in the drawing the cutter assembly 13 may be mounted on the upper platen 11 with the knives 14 pointing downward. In such a case of course the probe 16 is mounted on the lower platen 12 instead of the upper platen 11 and the gauge member 19 is still carried by the cutter assembly 13.

I claim:

1. In a cutter press comprising (a) upper and lower platens movable relative to one another (b) drive means for moving the paltens relative to one another (c) a cutter assembly including at least one cutting knife disposed between the platens to cut workpieces when the platens are moved together and (d) control means for controlling the movement of the platens, the improvement comprising a gauge memer arranged between the platens having a height which is in pre-determined proportionality to the height of the cutting knife and a probe operably connected to the control means to actuate the control means when engaged by said gauge member.

2. A cutter press according to claim 1, wherein the gauge member is attached to the cutter assembly so to form a constructional unit therewith and the member has an abutment surface carried on legs, which surface is parallel to the platens and serves to engage the probe.

3. A cutter press according to claim 1, wherein the probe is connected through a mechanical linkage to an electrical switch forming part of the control means.

4. A cutter press according to claim 2, wherein the probe is connected through a mechanical linkage to an electrical switch forming part of the control means.

5. In or for a cutter press comprising:

(a) upper and lower platens movable relative to one another (b) drive means for moving the platens relative to one another and (0) control means with a probe mounted on one of the platens for controlling the operation of the drive means; a cutter assembly with at least one cutting knife and a gauge member of a height which is in pre-determined proportionality to the height of said knife, the gauge member being adapted to engage the probe to actuate the control means when the press is in use.

References Cited UNITED STATES PATENTS 2,491,393 l2/l949 Purcell 83-525 X 2,781,844 2/1957 Pearson et al. 83525 X 3,450,037 6/1969 Lickliter et al. 83529 X FRANK T. YOST, Primary Examiner U.S. Cl. X.R. 83530 

